1. Field of the Invention
The present invention relates to a semiconductor device and a method of controlling the same, more particularly to a multi-chip package in which a plurality of memories is integrated in a single package.
2. Description of the Related Art
Normal CPUs read data from a nonvolatile read-Only memory (ROM), then transfer the data to a volatile random access memory (RAM) which is fast in data rewriting speed and perform operations upon the data. At a certain time, the data which has been operated upon is transferred from the volatile RAM to the nonvolatile ROM and retained in the ROM.
In recent years, a technique has been developed which packages a ROM and a RAM together (multi-chip package, which is hereinafter referred to as an MCP), which allows the area occupied by memories to be reduced (see, for example, JP-A No. 5-299616 [KOKAI]).
With the MCP technique, however, although the area occupied by semiconductor devices can be reduced, conventional control is merely used as it is for control of the ROM and the RAM. The MCP technique leaves room for improvement in transfer of data between the ROM and the RAM.